Manage bite wounds: not just skin deep

Manage bite wounds: not just skin deep

Inspiratory stridor common clinical sign with laryngeal paralysis
Jul 01, 2005

Bite-wound management can present significant and daunting challenges to the veterinary practitioner. One reason is that the patient may present with several fairly small puncture wounds in the skin, but the damage underneath the skin may be far more serious and extensive due to the tearing and shearing caused by the large canine teeth.

Significant trauma to vital structures of the neck, thorax and abdominal cavity may not be immediately apparent at first glance. A bite-wound patient can also progress from being "stable" to "crashing" in a remarkably short time. The following discussion highlights major points in bite-wound management and is illustrated by a short case report.

Respiratory compromise: In our practice, wounds to the head and neck of the canine victim account for a majority of all bite wounds inflicted by other dogs. This includes injuries to the upper respiratory tract, the larynx and the trachea. Also, bite wounds over the thorax may penetrate the pleural space causing a pneumothorax, hemothorax or a delayed pyothorax. If a bite-wound victim is in respiratory distress, it is important to determine whether it is upper-airway or lower-airway distress and should be treated accordingly.

This dog is suffering from significant soft-tissue damage in the ventral neck and evidence of penetration near the carotid sheath and trachea as a result of bite wounds.
In the upper airway, dogs can suffer from acute laryngeal paralysis if the recurrent laryngeal nerve, located adjacent to the trachea, is damaged from swelling or direct trauma. A common clinical sign associated with laryngeal paralysis is inspiratory stridor. Sedation with a low dose of acepromazine and/or butorphanol, or hydromorphone may be indicated. In cases that do not improve with sedation or in more extreme cases of cyanosis and hypoxia, immediate intubation and oxygen therapy may be necessary. A patient's temperature should be monitored closely as potentially life-threatening pyrexia may occur in cases of upper respiratory distress. The dog in Photo 1 suffered from bite wounds to the head and neck. On exploration of the wounds under anesthesia, there was significant soft-tissue damage in the ventral neck and evidence of penetration near the carotid sheath and trachea.

The damaged muscle was debrided and lavaged. When the patient was extubated, an inspiratory stridor and cyanosis were noted. Upon immediate re-intubation mucous-membrane color returned to normal. An oral examination revealed laryngeal paralysis. The suspected cause of the paralysis from inflammation effecting the recurrent laryngeal nerve along the trachea. A temporary tracheostomy was performed, and the tracheostomy tube was kept in place for four days while the swelling and inflammation resolved.

Lower-airway distress may be evident by tachypnea or dyspnea. Auscultation may reveal dull lung sounds, or crackles and wheezes. In a distressed and severely compromised patient, an immediate thoracocentesis may be indicated for diagnostic and therapeutic purposes. Radiography may prove helpful in making a diagnosis, but it is important to monitor for any respiratory distress and to minimize stress during this diagnostic test.

Shock Every bite-wound victim should be evaluated for signs of shock. Patients in shock should be stabilized with intravenous fluids, broad-spectrum intravenous antibiotics, and, in some cases, a blood transfusion. Patients in shock should be monitored for sepsis and/or disseminated intravascular coagulation.